Functional In Vitro Characterization of Two Novel Germinal STAT3 Mutations Associated with Short Stature, Immunedeficiency and Autoimmune Disease

KESELMAN, ANA; DOMENÉ SABINA; BEZRODNIK, LILIANA; ESNAOLA AZCOITI, M; REVALE, SANTIAGO; KUMAR, ASHISH; SCAGLIA, PAULA; KARABATAS, LILIANA; SANGUINETTI, NORA; CALDIROLA, MARIA SOLEDAD; HWA, VIVIAN; JASPER, HECTOR; GUTIERREZ, MARIANA; MARTUCCI, LUCIA; BLANCO, MIGUEL; DI GIOVANNI, DANIELA; HAWA-JONES, N; VAZQUEZ, MARTIN; DOMENE, HORACIO

Paris

Congreso; 55th Annual Meeting of the European Society for Paediatric Endocrinology (ESPE); 2016

European Society for Pediatric Endocrinology

Background: We have recently reported the molecular diagnosis of two patients with severe growth failure associated with a spectrum of early-onset autoimmune disease and immunodeficiency. Heterozygous de novo mutations, c.1847_1849delAAG (p.E616del) and c.1276T>C (p.C426R), in the STAT3 gene were found. Functional in vitro studies of these variants are presented. Objective and hypotheses: We aimed to study the impact of p.E616del and p.C426R mutations on STAT3 activity under basal and GH- or IL-6-stimulated conditions. We hypothesised that both variants are activating, since inactivating STAT3 mutations are associated with hyper-IgE syndrome without growth failure. Method: STAT3 gene variants were generated by site-directed mutagenesis and transfected into HEK293T cells. The effects of IL-6 (20 ng/mL) and GH (200 ng/mL) on expression, phosphorylation and transcriptional activity of WT and mutants STAT3 were studied using a luciferase reporter system and by Western Immunoblot. Results: Under basal conditions, variants p.C426R and p.E616del, presented increased reporter activity compared to WT-STAT3 (p